Articulated combine

ABSTRACT

Broadly, one aspect of the present invention is an articulated combine having increased on-board grain storage capacity (e.g., 1,200 bushels) and which is composed of a forward unit having an operator&#39;s cab, an engine, a grain harvesting assembly, a grain transfer assembly, and being devoid of an on-board grain bin; and a rearward unit jointedly attached to the forward section and having, steerable and powered wheels, an on-board grain bin for receiving grain from the forward section grain transfer assembly, and a grain off-loading assembly. The grain transfer assembly, joint, and grain off-loading assembly and controls, form other aspects of the present invention.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of application Ser.No. 09/481,046, filed Jan. 11, 2000; which is divisional application ofapplication Ser. No. 09/040,985, filed on Mar. 18, 1998, now U.S. Pat.No. 6,012,272; and is cross-referenced to application Ser. No.09/210,331, filed Dec. 11, 1998.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

[0002] Not applicable.

BACKGROUND OF THE INVENTION

[0003] The present invention generally relates to combines and moreparticularly to an articulated (jointed) combine which employs, interalia, an improved joint, unloading capability, grain transfercapability, airbag suspension, straw and chaff conveyor,suspended/movable fuel tank, control/steering, and extremely large grainstorage capacity.

[0004] A modern agricultural combine typically unloads or transfersclean grain from its on-board storage hopper utilizing an auger of fixedlength which swings out in a fixed radius and fixed elevation arc fromits stowed position. The stowed position generally is pointing to therear of the combine. The auger in turn generally is driven by amechanical arrangement of belts, chains, clutch, and gearbox. The unloadauger in most combine designs swings out to the operator's left. Theauger length generally is limited by the practical distance that it canextend beyond the rear of the combine in its stowed position withoutcreating a serious maneuvering hazard.

[0005] As the size of on-board storage hoppers and capacity of combineshas increased, the time required to maneuver the machine next to thegrain receiving wagon or truck and the grain transfer time have become amajor component of the total harvesting time. Conventional combines havea grain hopper capacity of 250 to 300 bushels and unload augercapacities of 1.9 to 2.6 bushels per second.

[0006] The unload time of the hopper typically is about 2 to 3 minuteswith the unload auger running at maximum speed and 1 to 2 minutes aretaken to maneuver the combine into the optimum unload position next tothe truck or wagon. Re-positioning the combine and running the auger atless than maximum speed are often encountered when topping off the truckor wagon which is receiving the grain. As modem combine harvestingcapacities approach 3,000 bushes per hour, the unload cycle must berepeated every 8 to 10 minutes. Therefore, the total unload time ornon-harvesting time is a significant reduction of total grain harvestingproductivity. A grain capacity of about 600-650 bushels would permit thecombine to harvest for about 1 mile, which would greatly reduceunloading cycles.

[0007] This productivity loss can be countered by a second operatorutilizing a tractor and grain cart following the combine back and forththrough the field to unload the on-board combine storage hopper withoutstopping the harvesting process. Alternatively, a combine with anintegrated grain cart, as disclosed in applicant's U.S. Pat. No.5,904,365 can be utilized to reduce the number of unload cycles and atleast double the rate at which grain is discharged to the receivingvehicle.

[0008] Unloading combines into semitrailer road trucks has become theprevalent practice as opposed to field wagons that were utilized in thepast. These road trucks typically are parked at the side of the road andnot in the field where the combine is operating. This necessary practicealmost always creates an elevational difference between the twovehicles. These road trucks themselves also have widely varying heights.These two conditions create a big variation in the optimum elevation ofthe discharge point of the combine unloading system. Combinemanufacturers have attempted to address this problem with ever-longeraugers and higher fixed swing out arcs. There are, however, limits toboth. This fixed point discharge point frequently ends up too high, toolow, too far from the combine, or too close to the combine for optimumtruck loading conditions. Such conditions require repositioning thecombine with respect to the vehicle while it is unloading.

[0009] Existing combine unloading systems can unload from one side ofthe machine only. This frequently requires 180° turns by the combine toposition it on the proper side to unload the grain into the road truck.It also means that while harvesting the combine generally only can beunloaded into a moving grain cart only while traveling along theleft-hand side of the unharvested crop since access to the unloaderwould be precluded by the unharvested crop were the combine to belocated to the right of the crop.

[0010] When topping off or completely filling the truck or wagon, it isnecessary for the operator to inch the combine forward or backwardduring the process. In addition to being cumbersome, the combine must bepositioned close to perfectly parallel to the receiving vehicle or astop and reposition is necessary. Moving the auger through its fixed arcfrequently cannot solve the lack of parallel orientation.

[0011] An agricultural combine has multiple steering requirements.Precise control is needed as the row harvesting units such as acornhead, are guided through the rows of grain. When the end of thefield is reached, a tight turning radius is needed to proceed backacross the field in order to harvest the crop immediately adjacent tothe just-completed rows or round. Concomitant with its fieldperformance, this large vehicle also must be controlled on the roadwayat speeds of around 20 mph and around tight corners. Another steeringassociated problem is to turn multiple axle, heavily-loaded bogies withlarge tires in a tight radius while minimizing sliding the tires in thehorizontal (particularly in the lateral) direction, which places highstresses in the suspension, piles up dirt in the field, and causesexcessive tire wear.

[0012] Early attempts at an articulated combine are reported in U.S.Pat. Nos. 4,317,326 and 4,414,794. The design capacity is stated to bearound 360 bushels. Its unloading mechanism is limited to one side ofthe combine and steering is accomplished only by articulation steeringcylinders. U.S. Pat No. 4,453,614 proposes a steering cylinderarrangement for an articulated combine. U.S. Pat. No. 4,204,386 proposesan articulated machine for gathering vegetables. U.S. Pat. No. 5,857,907proposes a discharge conveyor having a secondary, variably extendingconveyor attached to the terminal end of the discharge conveyor.

[0013] U.S. Pat No. 6,012,272 (the '272 patent) discloses an articulatedcombine composed of a forward unit or bogey having an operator's cab,engine, grain harvesting assembly, grain transfer assembly, but noon-board grain storage; and a rear unit or bogey jointedly attached tothe forward unit and having a steerable and powered wheel assembly, anon-board grain storage bin, and a grain off-loading assembly. Many ofthe industry long-felt, but unsolved needs regarding articulatedcombines are disclosed in the '272 patent. Basic improvements theretoare the subject of this application.

BRIEF SUMMARY OF THE INVENTION

[0014] One aspect of the present invention is a combine having increasedon-board grain storage capacity. The combine includes a forward unithaving an operator's cab, an engine, a grain harvesting assembly, agrain transfer assembly, and is devoid of an on-board grain bin. Thecombine also has a rearward unit jointedly attached to the forwardsection. The rearward unit has a powered wheel assembly, an onboardgrain bin for receiving grain from the forward section grain transferassembly, and a grain off-loading assembly.

[0015] Another aspect of the present invention is directed to a jointfor a powered articulated vehicle, such as a combine for joining aforward unit to a rearward unit. The joint includes an upper framemember carried by the forward unit and having a recess on its lower sideand a lower frame member carried by the forward unit, having a recess onits upper side, and being spaced-apart vertically below the upper framemember so that the recesses are in vertical registration. The jointfurther includes a shaft carried by the rearward unit and a bearingretainer assembly carried by the end of the shaft and disposed betweenthe recesses. The bearing assembly includes an outer annulus surmountingan inner hub which hub is connected to the shaft with thrust bearingsinserted between the annulus and said hub, whereby the inner hubco-rotates with shaft with respect to the outer annulus. The bearingassembly also includes a pair of nibs carried by the outer annulus whichnibs reside in the upper and lower recesses and which nibs areassociated with tapered roller bearings so that the outer annulusco-twists with the shaft respect to the forward unit. Uniquely, thejoint is stiff in the vertical plane through the longitudinal axisformed along the forward unit frame members and the rear unit shaft,i.e., around the pitch axis. It will be appreciated that the upper andlower frame members could be carried by the rearward unit and the shaftcarried by the forward unit and the novel joint would function the sameas with the configuration set forth above.

[0016] A further aspect of the present invention is an improvedarticulated combine comprising a forward unit connected by a joint to arearward unit. The improvement for transferring clean grain from theforward unit to the rearward unit includes the rearward unit carrying anonboard grain bin and having a front wall that has a horizontal slottherein. The front wall retains a horizontally elongate grain transfertrough affixed thereto which trough is curved with its center ofcurvature congruent with the center of articulation of the combine. Thetrough is in communication with the bin via the slot. The forward unitcarries a grain transfer assembly of a fixed elongate discharge chutethat empties into the rearward unit trough while the forward andrearward units are being turned about the joint.

[0017] A still further aspect of the present invention is a grainunloading assembly for unloading clean grain from a combine grain bin,wherein a combine harvests grain and cleans it to provide the cleangrain. Such grain unloading assembly includes a vertical flightedconveyor that is adapted to operate in either direction. Also includedis a housing in which the vertical flighted conveyor is disposed. Thehousing is fitted at its top with a bin spout, a discharge spout, amoveable door that permits communication of the flighted conveyor eitherwith the bin spout or with the discharge spout. A first opening at thebottom of the housing is covered with a moveable door for permittinggrain in the bin to be moved into the housing for conveying by theflighted conveyor. A second opening at its bottom of the housing is forpermitting clean grain to be passed into the housing from the combine.

[0018] Yet another aspect of the present invention is an unload assemblyfor unloading clean grain from a combine grain bin. This unload assemblyincludes a distal frame nested within a proximal frame. The distal frameis extensible from and retractable into the proximal frame. The distalframe has a discharge end for discharging grain. The proximal frame hasa feed end for receiving grain from the grain bin and a distal end fromwhich the nested distal frame extends and retracts. This unload assemblyfurther includes a conveyor system that includes a first fixed pulleylocated at the feed end of the proximal frame. A second fixed pulley islocated at the discharge end of the distal frame. A third fixed pulleyis located at the distal end of the proximal frame. A fourth moveablepulley is disposed within the proximal frame intermediate the first andthird fixed pulleys. The conveyor extends from the first pulley to thesecond pulley to the fourth pulley to the third pulley and back to thefirst pulley. A fifth pulley may be employed near the first pulley toincrease the wrap angle of the conveyor belt around the first pulley.This arrangement permits the conveyor to extend as the distal conveyorextends and retracts as the distal conveyor retracts by movement of thefourth pulley.

[0019] Still a yet further aspect of the present invention is a strawand chaff spreader for mounting in association with a grain cleaner of acombine. This spreader includes a pair of generallyhorizontally-disposed, outwardly rotating, cleated conveyors disposed toreceive straw and chaff discharged from the grain separator and cleanerof a combine.

[0020] A yet further aspect of the present invention is an airbagsuspension for a vehicle having a vehicle frame having an axle (stub orthrough axle) extending therefrom. A longitudinal beam is affixed to theaxle that carries at least one wheel. An airbag assembly includes anupper plate extending from the vehicle frame, a lower plate affixed tothe longitudinal beam, and an airbag disposed between the upper andlower plates. The lower plate carries a pair of vertical blocks havingvertical slots. A pair of cams is carried by the upper plate and ridesin the vertical slots.

[0021] Another aspect of the present invention is a steering system foran articulated vehicle having a joint that connects a forward unit and arearward unit and at least one articulation cylinder to provide aturning force at the joint. The steering system includes an operatorspeed and direction mechanism whereby an operator can direct the desireddirection of the vehicle. A power source is provided for driving pumpsadapted to drive motors and cylinders. The forward unit has tractivewheels (tired or tracked) powered by one or more motors. Each motor hasa transducer for measuring its rotational speed and direction. Therearward unit has a pair of tractive endless tracks or tired wheels eachpowered by a separate motor. Each motor has a transducer for measuringits rotational speed. A programmable controller receives the rotationalspeed measurements (for over-speed control) and pressures from all ofthe transducers and operator steering commands from the speed anddirection mechanism, and responds with suitable outputs. Actuatorsreceive the controller outputs and adjust the output of each of themotors powering the rearward unit tracks/wheels.

[0022] A still further aspect of the present invention is an improvedcombine having a fuel tank, and which includes an overhead rail fromwhich the fuel tank is suspended and an optional actuator connected tothe fuel tank for moving the fuel tank forwardly and rearwardly.Desirably, though, the fuel tank can be moved forwardly and rearwardlyby hand.

[0023] A still further aspect of the present invention is a method forarticulating an articulated vehicle at a rest position wherein thevehicle is composed of a forward unit and a tracked rearward unit havinga pair of powered tracks. The forward and rearward units are connectedby a joint and an articulation cylinder. The method powers up only onetrack while simultaneously actuating the articulation cylinder.

[0024] Advantages of the present invention include a combine design,preferably an articulated combine, which enables grain storage capacityof between 500 and 1,000 bushels or more. Another advantage is anarticulated combine which can unload clean grain to either side andwhich is controlled by a unique control system. A further advantage is aunique steering system for an articulated combine. These and otheradvantages will be readily apparent to those skilled in this art.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a fuller understanding of the nature and objects of thepresent invention, reference should be had to the following detaileddescription taken in connection with the accompanying drawings in which:

[0026]FIG. 1 is a side elevational view of the novel combine (orharvester) with, inter alia, extra large storage capacity, -straw andchaff conveyor, novel joint, clean grain transfer ability, and unloadingcapacity;

[0027]FIG. 2 is a side elevational view of the other side of the novelcombine depicted in FIG. 1. fitted with caster wheels at the rear of thefront unit;

[0028]FIG. 3 is an overhead view of the combine depicted in FIG. 1;

[0029]FIG. 4 is a rear view of the rear unit of the combine depicted inFIG. 1;

[0030]FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

[0031]FIG. 6 is a sectional view taken along line 6-6 of FIG. 5 showinga plan view in greater detail of joint 22;

[0032]FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

[0033]FIG. 8 is a sectional view like that taken along line 7-7, but ofa preferred embodiment of the joint of FIG. 6;

[0034]FIG. 9 is a sectional view taken along line 9-9 of FIG. 8;

[0035]FIG. 10 is an overhead view of the straw and chaff conveyor systemfitted at the rear of the front unit of the novel combine;

[0036]FIG. 11 is a side cut-away view of the rear unit of the novelcombine showing the grain transfer system between the front and rearunits and the grain handling system aboard the rear grain bin unit;

[0037]FIG. 12 is a rear cut-away view of the rear unit of the novelcombine showing part of the grain handling system aboard the rear grainbin unit;

[0038]FIG. 13 is a side cut-away view of the hydraulic nested grainoff-loading assembly in its retracted position;

[0039]FIG. 14 is a side cut-away view of the hydraulic nested grainoff-loading assembly in its extended position;

[0040]FIG. 15 is a partial side elevational view of a joystick used tocontrol the clean grain transfer assembly depicted in FIGS. 13 and 14;

[0041]FIG. 16 is a top view of the joystick shown in FIG. 15;

[0042]FIG. 17 is a schematic of the hydraulic vertical control for theclean grain transfer assembly of FIGS. 13 and 14;

[0043]FIG. 18 is a schematic of the hydraulic swing control for theclean grain transfer assembly of FIGS. 13 and 14;

[0044]FIG. 19 is a schematic of the hydraulic telescoping control forthe clean grain transfer assembly of FIGS. 13 and 14;

[0045]FIG. 20 is a schematic of the hydraulic speed control for theclean grain transfer assembly of FIGS. 13 and 14;

[0046]FIG. 21 is a side elevational view of the novel suspension systemof the rear grain bin unit;

[0047]FIG. 22 is a sectional view taken along line 22-22 of FIG. 15;

[0048]FIG. 23 is a sectional view taken along line 21-21 of FIG. 15;

[0049]FIG. 24 is a side elevational view of a combine like that depictedin FIG. 1, except that the rear unit is wheeled rather than fitted withan endless track;

[0050]FIG. 25 is a rear elevational view of the combine in FIG. 24;

[0051]FIG. 26 is an overhead view of the combine in FIG. 24;

[0052]FIG. 27 is a partial sectional view of the suspension system ofthe combine in FIG. 24;

[0053]FIG. 28 is a simplified overhead schematic of the turning geometryfor a wheeled rear unit embodiment of the present invention; and

[0054]FIG. 29 is a schematic of the hydraulic steering system for thenovel articulated combine.

[0055] The drawings will be described in detail below.

DETAILED DESCRIPTION OF THE INVENTION

[0056] The present invention provides basic improvements to the '272patent articulated combine, which disclosed solutions to many problemsassociated with modem farming combines by providing a harvester that canunload readily on either side and to virtually any height road truck.The disclosed harvester retains the increased capacity of harvestedgrain carrying capacity from about 200-300 bushels in conventionalcombines to about 500-1,200 bushels utilizing the rearward-only grainbin, because the rearward unit has more capacity (space) than there isin a grain bin located over a front axle. This is important because thecapacity of a typical road semi-trailer is 1,000 bushels. This meansthat the disclosed combine can fill an entire road truck from itson-board grain bin in a single unloading. Moreover, a unique, unloadingsystem permits unloading of clean grain from the rearward grain bin unitout to either side of the combine. Such increased grain storage capacityis possible because the grain bin is located on the rearward unit, whichpermits a much lower center of gravity to be designed into the rearwardunit.

[0057] In order to ensure that the extra weight can be easily maneuveredby the novel harvester, the rearward unit has powered and steerablewheels that are supported by a unique airbag suspension system. A newclean grain transfer assembly for transferring clean grain from theforward unit to the rearward cart bin unit also is disclosed. Animproved two-axis joint interconnects the forward and rearward units.Straw and chaff from the harvesting assembly is discharged to eitherside by a unique dual conveyor system. “Wheels” or “wheeled” for presentpurposes includes both wheels that are fitted with tires (pneumatictires) and wheels that are fitted with endless tracks.

[0058] Referring initially to FIGS. 1, 2 and 3, innovative combine 10generally includes forward unit 12 and rearward unit 14. Forward unit 12is seen to include cab 15 in which the operator is seated, cornhead orsmall grainhead 16, engine compartment 18 (two cooling fan air inletsshown in the drawings), and powered non-steerable wheel pair 20. In thealternative embodiment in FIG. 2, forward unit 12 is fitted with casterwheel pair 19 located at the rear of forward unit 12. Rearward unit 14is interconnected to forward unit 12 via joint assembly 22 and cleangrain is transferred from forward unit 12 to rearward unit 14 via cleangrain transfer assembly 24. Rearward unit 14 is seen to include cleangrain unloading system 26 in its stored position and in phantom in twopossible raised unloading positions in FIG. 3, grain bin 28, and poweredendless tracks 30 and 32. Use of a dual track system supporting grainbin 28 on rearward unit 14 contributes to the capability of grain bin 28holding upwards to 1,200 bushels of grain. Providing the grain bincapacity only on rearward unit 14 translates into a lower center ofgravity for grain bin 28 which also enables such higher storage capacityand provides more even weight distribution per axle. Importantly, atabout 600-650 bushel capacity of grain bin 28, combine 10 could harvest,for example, a cornfield for one mile before unloading. Capacity inexcess of requirement means that combine 10 can harvest for even greaterdistances before unloading.

[0059] As seen in FIG. 2, fuel tank 34 is carried suspended by rail 36and is moveable from a forward to a rearward position as indicated byarrow 38. Movement of suspended fuel tank 34 ensures access to, forexample, hydraulic lines and other components should such access benecessary, desirable, or convenient. Such fuel tank movement alsoenables weight shifting of forward unit 12, should such weight shiftingalso be necessary, desirable, or convenient.

[0060] As seen in FIG. 4, grain bin 28 is fitted with ladder 40 foroperator access to the interior of grain bin 28. Grain bin 28 also isfitted a pair of light arrays, 42 and 44, as the combine may traverseroadways in order to access field to harvest. Other items of interest inthis rear view of the combine will be discussed later in connection withother features of the novel articulated combine.

[0061] Referring to FIGS. 5, 6 and 7 that illustrate joint 22,initially, it will be observed that a pair of steering cylinders, 46 and48, are seen in FIG. 5 to connect forward unit 12 to rearward unit 14 ofarticulated combine 10. Such steering cylinders are conventionally usedto assist in the steering of articulated vehicles and are provided herefor such steering use in the present articulated combine design. Now,with respect to the two-axis joint, pipe 50 is attached to rearward unit14 at one end and is constructed as a round pipe or structural tube.Shaft 52 extends from pipe 50 towards forward unit 12 and is insertedinto bearing retainer assembly 60 which is inserted between upper framemember 54 and lower frame member 56. These frame members 54 and 56 arebolted to forward unit 12 via bolts 58 a-d; although, other attachmentmeans certainly can be envisioned. Each frame member 54 and 56 has aninner recess that confronts the corresponding recess in the other andinto which is inserted bearing retainer assembly 60.

[0062] Bearing retainer assembly 60 has a pair of nibs or ears which fitinto frame member 54 and 56 recesses and which ride on tapered rollerbearing 62 a-62 b to provide sideways movement to units 12 and 14 viapipe 50. Such sideways movement permits combine 10 to be steered. A holepenetrates through bearing retainer assembly 60 into which areduced-diameter threaded end of shaft 52 fits and is secured via nut64. Now, thrust bearings 66 and 68 fit into counterbores that adjoin thehole through bearing retainer assembly 60 and which thrust bearingspermit shaft 52 to rotate and which, thus, enables units 12 and 14 torotate with respect to each other. Such rotation permits units 12 and 14to traverse uneven terrain during harvesting or other movement ofcombine 10. Note, however, that pipe 50 and shaft 52 are not permittedto move in a vertical direction due to the unique construction of jointassembly 22. Thus, a unique dual axis joint has been disclosed. Itshould be understood that the connection of joint 22 could be thereverse of that connection depicted in FIGS. 5, 6, and 7. That is, pipe50 could be attached to forward unit 12 rather than rearward unit 14.

[0063] A modified version of the joint depicted in FIGS. 6 and 7 has nowbeen designed and is illustrated in FIGS. 8 and 9. It utilizes thefeatures of joint 22 of FIGS. 6 and 7, except that additional thrustbearings have been added to take up the additional separational forcesthat joint 22 sees due to taped roller bearings 62 and 66. Also, thejoint in FIGS. 8 and 9 has been rotated 180° so shaft 52 now isconnected to forward unit 12, rather than to rearward unit 14 via pipe50, as is shown in FIGS. 6 and 7. Also, frame members 54 and 56 areremovably attached to frame member 59 that is connected to rear unit 14.Additionally, spacers 51 are held in place by threaded bolts 53 and 55,which fit through holes in frame members 54 and 56, respectively. Thebasic construction of the joint in FIGS. 8 and 9 is like that for joint22, except that frame members 54/56 have apertures into which flangedplug assemblies 70 and 72 are placed and held securely by threadedmembers 74 and 76, respectively. Recesses adjacent the apertures inframe members 54/56 contain races into which thrust bearings 78 and 80,respectively fit and are retained by the flared heads of flanged plugs70 and 72. Flanged plug assemblies 70 and 72 include spacers (not shownin the drawings) to ensure that tapered roller bearings 62 and 66 arenot excessively pre-loaded when flanged plugs 70 and 72 are tightenedand washers (not shown in the drawings) are provided for the flanges ofplugs 70 and 72 to bear against when tightened.

[0064] Regarding to the novel two-axis joint as disclosed in the '272patent, unique to joint 22 is that it is a “single point” joint. Thatis, joint 22 is designed to be only about a foot or so high. No otherstructural connection between forward unit 12 and rearward unit 14 isrequired by dint of the design of joint 22. That is not to say thatother structural connection cannot be made between forward unit 12 andrearward unit 14, but that no other structural connection is necessary.In fact, it is a positive advantage that no other structuralinterconnection is needed between the two units because the combinedesigner has greater flexibility in locating equipment, lines, feeders,etc. because of the single point joint design disclosed herein.

[0065] Referring now to FIG. 10, the description will commence with thetransfer of clean grain from forward unit 12 to grain bin 28 and will becompleted with off-loading of the grain into, e.g., a semi-truck. Inthis regard, clean grain and straw and chaff separately exit from graincleaner assembly 82 (which is quite conventional). The straw and chafffalls down onto dual conveyors 84 and 86 that are separately driven byhydraulic motors 88 and 90, respectively. Alternatively, conveyors 84and 86 could be driven by a single motor with appropriate gearing,belts, or the like, providing for the movement of the non-drivenconveyor either in the same direction or in the opposite direction fromthe driven conveyor. Conveyors 84/86 also can be seen in FIGS. 1-3 to belocated above joint assembly 22. In normal operation where combine 10 istraveling through the field harvesting grain, conveyors 84 and 86 eachrotate so as to throw the straw and chaff outwardly from combine 10.During a turn, it may be advantageous to not bunch up straw and chaffunder the rear wheels of rearward unit 14, so both conveyors can be setto throw the straw and chaff to the side of combine 10 that is oppositethe direction of the turn. Since conveyors 84/86 desirably areseparately powered, they can be rotated in the same direction or inopposite directions. Regardless of the direction of their turning,conveyors 84/86 ensure that the straw and chaff will not fall down onjoint assembly 22 nor bunch up directly underneath combine 10 forrearward unit 14 to traverse over.

[0066] The clean grain from the grain cleaning operation aboard forwardunit 12 travels to clean grain transfer assembly 24 (see FIGS. 1-3 and11). Referring especially to FIG. 11, it will be observed that cleangrain passes down fixed elongate discharge chute 92 into elongatehorizontal trough 94 that is connected to the forward wall of grain bin28. From FIG. 3, it can be seen that the front of trough 94 is curved(or arcuate) to match the radius of curvature of articulation of combine10. Such curvature ensures that fixed chute 92 always will empty cleangrain into trough 94 even while combine 10 is turning (articulating).Now front wall 96 of grain bin 28 has slot 98 that permits clean grainin trough 94 to be passed to the inside (or cavity) of bin 28. Thedesign of clean grain transfer assembly 24 is simple in that gravity isused to feed the clean grain from forward unit 12 into trough 94 viachute 92. Gravity also ensures that the clean grain in trough 94 passesthrough slot 98 into grain bin 28.

[0067] The clean grain passing through slot 98 enters vertical conveyorsystem 100 that passes the clean grain into bin 28 and also to cleangrain off-loading assembly 26. As such, vertical conveyor assembly 100is central to proper grain handling within grain bin 28. To that end,vertical conveyor system 100 includes flighted (paddled) conveyor 102disposed within housing assembly 104. Conveyor 102 is driven byhydraulic motor 106 (see FIG. 4) and its direction is reversible and itsspeed is variable. At the top of conveyor assembly 100 are a pair ofdischarge chutes, 108 and 110 (which will be described later). Moveabledoor 112 powered by hydraulic cylinder 115 (see FIG. 2) permits cleangrain to be discharged either by chute 108, chute 110 or both with thedirection of conveyor 102 being coordinated with the position of door112. With door 112 in the position shown in FIG. 11, conveyor 112 wouldbe set to rotate in the counterclockwise direction by motor 106 (thedirection of rotation is given with respect to FIG. 11, as direction ofmovement is determined by the position of the observer). Grain enteringhousing 104 via slot 98 would be discharged into grain bin 28. When door112 is moved into the dashed line position and the direction of conveyor102 reversed, grain would be discharged through chute 110 into unloadassembly 26, which will described in detail below. It is possible tounload bin 28 while harvesting as also will be described below. Due toall the grain being dumped into bin 28 through chute 110, top levelingaugers also can be provided to even out the clean grain stored in grainbin 28.

[0068] To continue with the flow of clean grain, once clean grain entersbin 28, it is stored there until it is required to be discharged.Referring to FIGS. 3, 5, 11, and 12, the first step is clean graindischarge commences with a unique floor design that includes dragpaddles 114 and 116 that are powered by hydraulic motor 118 (see FIG. 4)that can be accessed via door 120 at the rear of grain bin 28. Dragpaddles 114/116 essentially create a fluidized bed of grain that is fedfrom bin 28 through moveable door 122 that is powered by hydrauliccylinder 124 (see FIG. 11) and into housing 104. It will be appreciatedthat augers or the like could replace drag paddles 114/116; although,the flatness of paddles permits bin 28 to have a flat floor whichincreases the grain capacity of bin 28. In order to prevent the grain inbin 28 from stopping the movement of drag paddles 114/116 and in orderto meter grain to such drag paddles, adjustable inverted-V floorassembly 126 is stationed just above drag paddles 114/116 (see FIGS. 3and 12). Moveable doors or the like could substitute therefor. It willbe appreciated that each inverted-V (e.g., V 128) retains a pair ofadjustable louvers (e.g., louvers 130 and 132) that can finely adjustthe openings between each inverted-V. Such louver arrangement providesfor precise metering of grain from bin 28 to drag paddles 114/116.Louvers 130/132 can be adjusted manually; although, hydraulic adjustmentcould be provided.

[0069] Now that drag paddles have pulled/pushed the clean grain intohousing 104, if conveyor 102 rotated in a clockwise direction with door112 actuated to the dashed line position (i.e., chute 108 closed andchute 110 open), then clean grain in bin 28 will be conveyed by conveyor102 up through housing 104 and be discharged via chute 110 onto cleangrain unloading system 26. Should combine 10 be harvesting field grainwhile off-loading is progressing, then not only will grain housed withingrain bin 28 be off-loaded (unloaded), but so too will clean grainentering housing 104 via slot 98 from grain transfer system 24. Thus,the novel combine has the capability of harvesting and unloading grainconcurrently. Once clean grain in grain bin 28 has been off-loaded, door112 is moved to its position as shown in FIG. 11 and conveyor 102reversed in its direction of travel to then throw clean grain back intobin 28.

[0070] Clean grain unloading system 26 (see FIGS. 2 and 13) includesnested conveyor assembly 134, which includes distal frame 136 with grainchute 137 nested within proximal frame 138. Housed within frames 136/138is cleated (or flighted) endless conveyor belt 140. Nested conveyorassembly 134 rests on cradle 142 that is formed from a shaft (not seenin the drawings) and rollers, such as roller 144 (see FIG. 3). Cradle142 permits the nested conveyor assembly 134 to move along itslongitudinal axis with respect to cradle 142 when combine 10articulates. Rotational power is not supplied to conveyor assembly 134when no clean grain unloading is taking place so that it is in a floator relaxed mode; thus, permitting conveyor assembly 134 to be rotated bycradle 142 when combine 10 articulates. Chute 110 transfers clean grainthrough an aperture in proximal housing 138 directly above the pivotpoint, pivot assembly 146 (see FIGS. 13 and 14), for conveyor assembly134 so that the transfer location does not change as the conveyorrotates from side to side during unloading.

[0071] Nested conveyor assembly 134 is lifted by pistons 148 and 150,which are attached to cable 152 that runs through snatch block 154 whichin turn is connected to rearward unit 14 by frame assembly 156 (seeFIGS. 2 and 3). Such lifting mechanism also has its pivot point in linewith the axis of rotation of conveyor assembly 134 so that conveyorassembly 134 does not change height as it is rotated from side to side,such as is shown in phantom in FIG. 3. Such lifting mechanism'sconnection to rearward unit 14 is moment decoupled to prevent conveyorassembly 134 from twisting as it rotates by means of the universalattachment of snatch block 154 which is permitted to move in all threeaxes. Alternatively, rod end Heim joints could be placed at the ends ofan adjustable rod in place of cable 152.

[0072] Referring to FIGS. 2, 11, 13, and 14, nested conveyor assembly134 is rotated from side-to-side by wheel or sprocket 158 that issupported by shaft 159 for rotation of sprocket 158, a chain thatencircles sprocket 158 (not readily seen in the drawings), and hydraulicmotor 160 which pulls the chain through a small sprocket (also notreadily seen in the drawings). Conveyor assembly 134 is supported bypivot assembly 146, which permits conveyor assembly 134 to be inclinedupwards. The center of wheel 158 establishes both the axis of rotationand the axis of inclination of conveyor assembly 134. Pivot assembly 146includes a shaft disposed vertically through its center hub, which shaftis supported by an outer hub that is tied to rearward unit 14 viastructure 162. Additional structural stability and support (not shown inthe drawings) for wheel 158 is provided by cam follower-type rollersthat are disposed under the periphery of wheel 158 and tied to structure162. This additional support can be helpful as the conveyor rotateswhich causes a torque load to be introduced into the center supportshaft at various angles.

[0073] Endless conveyor 140 is driven by hydraulic motor 164 (see FIG.2), which connects to drive pulley 166 (see FIGS. 13 and 14). From fixeddrive pulley 166, belt 140 goes to stationary pulley 168 located indistal frame 136, back to moveable pulley 170, to fixed pulley 172, toidler pulley 174, and back to drive pulley 166. Note that moveablepulley 170 is located between fixed pulleys 166 and 172. As distal frame136 is extended from proximal frame 138 by hydraulic motor 151associated with pinion 153 and rack 155, pulley 170, which otherwise isbiased inwardly, moves from a position such as is illustrated in FIG. 13to a position such as is illustrated in FIG. 14. Hydraulic motor 151 ismounted at the distal end of proximal frame 138 along with pinion 153.Rack 155 is mounted at the proximal end of distal frame 136 and isdriven by pinion 153 to extend/retract distal frame 136. Chute 137 inturn extends from its home Dosition to an extended position so thatclean grain can be unloaded, for example, into a waiting semitrailer.Frames 136 and 138 preferably are shrouded or covered to aid in grainretention during operation of belt 140.

[0074] With respect to operation of clean grain unloading system 26,reference is made to FIGS. 15 and 16 which show the unique joystickcontrol system of the '272 patent which can be adapted to control thepresent unloading system. Initially, joystick 200 is fitted with fingertoggle switches 202, 204, 206, and button 208. The operator's fingersactivate toggle switch 202 that causes unloading system 26 to movevertically up and down. Switch 204 conveniently is thumb activated andis an on-off switch for unloading system 26. Switch 206 is a combineinching switch; that is, it causes combine 10 to move slowly forward orbackward to place spout 137 exactly where the operator desires. Suchslow movement is known as “inching” in this field. Button 208 is a“home” button that means that unloading system 26 is returned to itsstored position as shown in FIG. 3, for example.

[0075] Another capability of joystick 200 is that it can move forward,backward, and laterally left and right. These movements cause unloadingsystem 26 to extend (say, forward movement of joystick 200), retract(backward movement), swing to the left (left movement), and swing to theright (right movement). Finally, joystick 200 is rotatable to controlthe speed of the belt 140 of unloading system 26.

[0076] Joystick 200 accomplishes the described movements of unloadingsystem 26 by signaling electrohydraulic valves with a signal sent tomanually adjustable flow control valves for, say, movement of unloadingsystem 26 up/down, left/right, in/out, and home. Joystick 200 signals aproportional servo valve for on/off and conveyor speed (e.g., activatesa linear electric servo that moves a pump swash plate). Joystick 200signals the propulsion system of combine 10 in order to inch the combineforward or reverse by by-passing the normal operator speed control ofthe vehicle. It should be obvious that the novel combine takes advantageof the hydraulic system already in place in conventional combines andextends their use in order to power desirably the unloading system 26and tracks 30 and 32. Other power means, of course, could be employed;however, hydraulic power tends to be more reliable.

[0077] In the unloading or off-loading mode, belt 140 always is actuatedfirst and turned off last in order to minimize any plugging problems.Next, the direction of vertical conveyor 102 is reversed from the grainharvesting mode and its speed is increased. Door 122 is opened and grainfed by gravity to conveyor 102 until a sensor indicates that the amountof gravity fed grain slows down. At this point, drag paddles 114/116 areactivated to feed conveyor 102.

[0078] Implementation of such joystick movements of unloading system 26is displayed in FIGS. 17-19. Referring initially to FIG. 17, lines 210and 212 are connected to a source of voltage (say, 12 volts supplied bythe combine). Contacts 214 and 216 are joystick 200 contacts for raisingand lowering, respectively, conveyor assembly 134 of unloading system26. Ground 217 is provided in conventional fashion. Upon closure of oneof joystick contacts 214 or 216, bidirectional valve with adjustableflow 218 is fed hydraulic fluid at, say, 2,000 psi from a hydraulic pumpwhich feeds rod and cylinder assemblies (pistons) 148/150 via lines 220and 222 with oil returned to reservoir 224 via line 226. Assembly 134,then, raises and lowers unloading system 26 (conveyor assembly 134).

[0079] Referring to FIG. 18, lines 228 and 230 run to joystick contacts232 and 234 which actuate bi-directional valve with adjustable flow andfloat 236 which actuates motor 160 for swinging unloading system 26either left or right. Ground 238 and return line 239 to reservoir 224are provided in conventional fashion. A rod and cylinder or other meanscould be substituted for motor 160.

[0080] Referring to FIG. 19, lines 240 and 242 run to joystick contacts244 and 246 which actuate bi-directional two flow valve (slow/fastspeed) 248 which actuates motor 151 for extending distal frame 136 fromits nested position within frame 138. Ground 250 and return line 254 toreservoir 224 are conventionally provided. A rod and cylinder or othermeans could be substituted for motor 151.

[0081] Referring to FIG. 20, the unload system speed control is shown.Specifically, combine engine 256 is connected via line 258 to pump 260,which is a variable displacement pump. Pump 258 is in fluid (oil orhydraulic fluid) communication with motor 106, which runs verticalconveyor assembly 102, via lines 262 and 264 that form a hydrostaticloop. Pump 260 is controller/actuated via joystick 200 as follows. Line266 runs through on/off switch 268 and combine speed potentiometer 270(actuated by joystick 200) to servo controller 272, which in turn isconnected via line 274 to servo actuator 276 that is connected to pump260 via line 278 for moving the swash plate of pump 260 to control thespeed and direction of vertical conveyor assembly 102 via motor 106.Line 280 runs through on-off switch 282 and unload speed potentiometer284 to servo controller 272 (also actuated by joystick 200). Now, lineon/off switch 268 is on (and switch 282 off) when combine 10 is not inan unloading mode, i.e., the combine is idle or harvesting grain. Switch282 is turned on (and switch 268 off) when the operator desires tooffload grain from combine 10. In this manner, the operator can controlthe speed of vertical conveyor assembly 102 via motor 106. It will beappreciated that the function of switches 268 and 282 could be combinedinto a single switch unit.

[0082] When the operator desires to off-load grain from grain bin 28,the operator also needs to control drag paddles 114/116 and belt 140.This is accomplished via on/off switch 281 (controlled by joystick 200)in line 283 that runs to solenoid-operated valve 284 that is disposed inline 286. Valve 284 is actuated by pump 288 that is powered by engine256 via line 290. Now, line 286 from valve 284 runs to hydraulic motor164, which runs belt 140, with the oil in line 286 returning to tank292. On/off switch 294 (also controlled by joystick 200) in line 295runs to solenoid-operated valve 293 that is disposed in line 291 thatbranches from line 286. Line 291 runs to hydraulic motor 118 that runsdrag paddles 114/116, with the oil returning to tank 292. At this pointin the description it should be noted that reservoir 224 is notated onthe drawings as the reservoir for all hydraulic fluid circuits.Obviously, additional reservoirs could be used as is necessary,desirable, or convenient.

[0083] The novel airbag suspension system now will be described withspecific reference to FIGS. 21-23 for an endless track system; although,such airbag suspension system can be adapted for tired wheels (see FIGS.24-27 and the description thereof) and for a variety of articulatedvehicles (e.g., other farm vehicles, earth moving equipment (bulldozers, excavators, cranes), buses, mining equipment, etc.) in additionto combines. Endless track system 298 generally includes endlessmetallic sectioned or rubber traction belt 30 is seen to be mountedaround drive wheel 300 (wheel and hydraulic motor assembly) and idlerwheel 302. Additional intermediate idler wheels 304-312 are conventionalin use, location, and function, and generally ensure contact of track 30with the ground. Track system 298 is connected to frame member 314 ofgrain bin 28 (see FIG. 12) by stub axle 316. Another endless tracksystem 296 (see FIG. 23) is disposed opposite track system 298, but willnot be described in detail herein as it is a mirror image of tracksystem 298. Track system 296 is supported by frame 315 as seen in FIG.12.

[0084] Each track system 296/298 has a pair of airbag suspensionsystems, e.g., 318 and 320 airbag systems (nominal rating of, e.g.,10,000 pounds) for track system 298. Referring specifically to airbagsystem 320, airbag 322 will be seen to be retained by upper plate member324 that is connected to frame member 314 and rests on lower plateassembly 326. Lower plate assembly 326 is connected to walking beam 328,which is supported by stub axle 316. Lower plate assembly 326 has a pairof upstanding forward and rearward members, 330 and 332. Each upstandingmember 330/332 has a race or slot in which rides a cam follower, e.g.,cam follower 334 for upstanding member 330. Cam follower 334 (and theother cams not visible in the drawings) are connected to upper platemember 324 are free to move vertically, but are restrained from movinghorizontally. Thus, the cam followers dramatically reduce the largemoment in the axle caused by the tracks sliding as combine 10 turns.Note should be taken that while stub axle 316 can be located at thelongitudinal center of grain bin 28, it may be advantageous to locate itforward of such center of gravity so that grain bin 28 always is liftingup on joint 22. Also, walking beam 328 with its mounting only by stubaxle 316 permits about a 12 inch rise and fall of each of its ends,i.e., wheels 300 and 302 can move ±12 inches to accommodate uneventerrain.

[0085] The same type of airbag suspension system can be adapted fortired wheels as was described for tracked wheels. Reference is made toFIG. 24 in this regard whereat articulated combine 350 is shown to haveits rearward unit 352 supported by tired wheels 354 and 356 on one side,and on the other side by tired wheels 358 and 360 (see also FIGS. 25 and26). Each tired wheel 354/356/358/360 is separately powered by ahydraulic motor 362/364/366/368, respectively. Each forward tired wheelalso is designed to be turned about 15° by a hydraulic cylinderarrangement as seen in FIG. 26 wherein cylinder 394 is seen connectedfrom beam 384 to knuckle 396 for tired wheel 358 and cylinder 397 isseen connected from beam 382 to knuckle 398. Cylinders 394 and 397 arehydraulically actuated and can be integrated into the steering system ofcombine 10.

[0086] Tired wheels 356 and 358 are joined together by tie rod assembly391, which connects knuckle 396 with knuckle 398. Tie rod assembly 391passes through grain bin 28 at about its center, that is, where beams382 and 384 are attached to axles 378 and 380, respectively, in order tominimize the affect that the ups and downs that tired wheels 356 and 358would generate as combine 10 traversed over uneven ground. Finally,spring assemblies 393 and 395 are mounted in associated with tiredwheels 360 and 354, respectively, and bias tired wheels 360 and 354 to aneutral or straight-ahead configuration. Tired wheels 360 and 354 arepermitted to rotate slightly during a turn of combine 10 and springassemblies 393 and 395 return the wheels to a straight-ahead position.

[0087] The reason for permitting rear tired wheels 354 and 360 to“free-wheel” rotate slightly during a turning of front tired wheels 356and 358 is due to the geometry of turning an articulated vehicle. Thiscan be seen by referring to FIG. 28 wherein an overhead simplifiedschematic of combine 350 is seen to include forward unit 351, having oneset of wheels, and rearward unit 352, have two pairs of wheels. Now,during a turn of articulated combine 350, each set of wheels must be onan arc that meets at center 502 of the radius of the turn. Thecorresponding radii for each set of wheels are identified by radius 504for the wheels of forward unit 351, radius 506 for tired wheel 358,radius 508 for tired wheel 356, radius 510 for tired wheel 360, andradius 512 for tired wheel 354. One consequence of the turning geometryis permitting rear tired wheels 354 and 360 to rotate slightly toconform to the turning radius, with spring assemblies 393 and 395biasing them back into a straight position. Another consequence is thatfront tired wheels 356 and 358 can be turned along the same radius andstill an acceptable turning scheme would be present; although, theirradii are slightly different. Structuring a steering control system,then, accommodates the turning geometry illustrated in FIG. 28.

[0088] The airbag suspension system still is used; albeit in a slightlymodified condition. That is, airbags 370/372/374/376 are retained byframes and utilize cam follower assemblies, 386, 388, 390, and 392, asdescribed above. Stub axles 378 and 380 support walking beams 382 and384, respectively, which in turn support the airbag assemblies. Thus,each tired wheel 354/356/358/360 has the ability to rise and fall, forexample, ±12 inches, to accommodate uneven terrain. FIG. 27 illustratessuch construction in greater detail and taken in conjunction with FIG.26. The remainder of operation of articulated combine 350 is the same asdescribed above with respect to articulated combine 10.

[0089] Now, with respect to steering and controlling articulated combine10, several unique problems are encountered. Prior art articulatedvehicles typically use hydraulic cylinders mounted across thearticulation joint to produce steering force. The cylinders arecontrolled by a rotary valve mechanically connected to a steering wheelthat is positioned by the operator to achieve the desired turn orvehicle direction. This system is used primarily on wheeled (tired)vehicles that have one axle in front of the joint and one behind thejoint, such as an agricultural tractor; or two axles behind the joint,such as a mining truck. Typically, the wheels on the axle, which arepowered, are connected together and receive power from a mechanicaldifferential. The differential permits a speed difference to be createdbetween the two tired wheels which speed difference is required to turnwith a reasonable amount of force from the articulation cylinders. Toinitiate a turn in such an articulated vehicle, its also is necessary toslide or rotate the portion of the tires that are in contact with theground or supporting surface. This generally is feasible since thecontact patch or portion of the tire diameter in contact with thesupporting surface generally is relatively small with respect to thediameter and width of the tires. Such tire sliding or rotating usuallycan be accomplished with a reasonable amount of force from the steeringcylinders at the articulation joint.

[0090] In an articulated combine wherein the rear module is supported byendless tracks powered by individual motors, such as is disclosed inapplication Ser. No. 09/210,331, cited above, the steering forces arequite different from the tired vehicle just described. The endlesstracks provide a much larger contact patch than do tires and, therefore,a much higher resistance to sliding or rotating them is encountered whena turn is initiated. The contact patch area also is elongated, whichfurther increases the force required from the articulation cylinders toinitiate a vehicle turn and to recover from a turn, which maneuver alsorequires sliding of the tracks laterally to position the vehicle in astraight alignment.

[0091] The steering forces are increased further when individual motorsare used to power the tracks, rather than a single motor and amechanical differential to interconnect the two tracks. When individualmotors on each track are used, such motors typically receive hydraulicpower from a common supply, whether such supply is one pump or two pumpsthat are interconnected at their output ports. The common supply isnecessary in a conventional system to ensure that the motors will sharethe propulsion load since they are mechanically interconnected by thesupporting surface under the vehicle. The common supply provides thesame pressure to all motors, which means that each motor will producethe same torque or thrust when the system is in equilibrium and thevehicle is moving in a straight line. In order to initiate a turn, thesteering cylinders must provide sufficient force to change the arc oftravel of the tracks and establish an inside track and an outside trackrelationship that establishes a speed differential between the twotracks. The cylinders must overcome the natural tendency of the motorsto run at the same speed and to share equally the tractive effortrequired to move the vehicle. The cylinders must force an articulationangle that forces a portion of the tractive load to move to the insidetrack, which causes the pressure to go down in the outside track due toits mandated increase in speed. Hydraulic fluid flow to the outsidetrack motor increases immediately following the path of least resistanceuntil the pressure in the two motors equalizes. This process occurs anytime the articulation angle changes during a turn of the vehicle. Thesteering cylinders, therefore, must not only have sufficient force toslide or rotate the tracks, but also to create a backpressuredifferential between the two motors. The motors, thus, are resistingboth the initiation of a turn and a recovery from a turn.

[0092] The described problem can be reduced by using the differentialsteering techniques in conjunction with articulation cylinders asdisclosed in application Ser. No. 09/210,331, cited above. Animplementation of such improved technique is described below inconnection with FIG. 29.

[0093] System Elements:

[0094] A power source, which typically is an internal combustion enginedisposed in forward unit 12 and which drives hydraulic pumps, which inturn function as a controlled source of power for hydraulic motors andcylinders.

[0095] A support and tractive means on the front unit (e.g., wheel pair20) powered by a hydraulic motor driving through a mechanicaldifferential; although, use of individually driven tracks and tires canbe used.

[0096] An articulation joint (e.g., articulation joint assembly 22) thatincludes at least one articulation cylinder and rod assembly (e.g.,hydraulic cylinder 46 or 48) to provide turning force wherein thecylinder is powered by a steering valve directing the flow from ahydraulic pump. The steering valve is controlled by the operator using asteering device, such as a wheel, or can be controlled by an automaticguidance system.

[0097] A support and tractive means for rearward unit 14 (e.g., endlesstrack assembly 298). Usually, there are two such track assembliesseparately and independently powered by individual hydraulic motors,which receive power from a pair of hydraulic pumps, each dedicated to asingle hydraulic motor. Each motor includes a transducer or sensor thatmeasures the rotational speed of the motor and provides that informationto a control system.

[0098] A programmable controller (e.g., CPU), which receives steeringand propulsion information from measurement transducers, performspreprogrammed or adaptive logic functions, and directs propulsion andsteering elements to implement the vehicle maneuvers commanded by theoperator or automatic guidance system.

[0099] An actuator, which receives commands form the programmablecontrollers and adjusts the output of the hydraulic pumps poweringendless track assembly 298 (and a similar assembly on the other side ofrearward unit 14) to cause the motors to execute the operator's desiredvehicle maneuvers. These actuators typically are digital stepping motorsthat are adjusting the pump mechanism, which sets its output. In atypical hydrostatic pump, this mechanism is called a swash plate, whichsets the stroke of the pistons that determines the output flow of thepump.

[0100] System Characteristics:

[0101] Motor speed is determined by the oil flow rate from the pump.

[0102] Motor torque is determined by the pressure applied to it up tothe setting on the relief valve, which opens at a preset pressure andallows hydraulic fluid to bypass the motor and flow back to thereservoir.

[0103] The load the motor is seeing at any point in time determines thepressure in the hydrostatic pump/motor loop. The swash plate in the pumpis establishing a flow rate to the motor. The pump will attempt toalways maintain that flow rate and the pressure rises or subsides asneeded to keep the motor rotating at a speed to accept that flow.

[0104] It is, therefore, possible to make multiple motors load share oraccept a disproportionate share of the total system load by controllingthe pressure of the hydraulic fluid flowing to them. This assumes thattraction will allow the load share or shift to occur, which dictates aspeed limiting control loop since the individual pumps are notcross-connected. If the motor is speeded up by increasing the pressureto it in order for the motor to take on a greater load and the trackpowered by such motor cannot achieve sufficient traction, the motor willoverspeed. The only controllable variable in the pump is flow bychanging the swash plate. However, motor pressure/torque/speed can becontrolled, assuming sufficient traction is available and the motor issized adequately to overcome the load placed on it, by controlling theflow of hydraulic fluid the pump is trying to force through it.

[0105] System Objectives

[0106] To cause the motors to share the forward or reverse propulsionload within i 5% when the steering load on the articulation cylinders isless than a defined amount, say, 1,000 psi.

[0107] To assist the articulation cylinders to execute a turn wheneverthe cylinder pressure in either direction goes above 1,000 psi. Note:1,000 psi is exemplary, but based upon results of testing thearticulated tracked combine disclosed herein. Such figure may vary oncefurther acceleration or starting on grade testing is undertaken. In thissituation, the pressure reference may not be as stable as speed andlikely will change with the load.

[0108] The foregoing system elements, characteristics, and objectivesare embodied in FIG. 29. Specifically, inputs to micro-controller 400include left steering pressure signal 402 and right steering pressuresignal 404 from steering valve 406, which is actuated by the operatorrotating steering wheel 408. Signals 402/404 also are fed to leftarticulation cylinder 46 and right articulation cylinder 48 with lines410 and 412 supplying the necessary interconnection between cylinders46/48 and lines 410/412. Such interconnection is the primary steeringmechanism for articulated combine 10.

[0109] The operator indicates the desired speed of combine 10 throughlever 414 which is connected by line 416 to front axle pump 418 whichdrives front motor drive 420. Lines 422 and 424 interconnect pump 418and motor 420 with lines 426 and 428 providing two more inputs tocontroller 400. Potentometer 430 provides a reference signal via line432 to controller 400. Left track pump 434 powers left track motor 436via lines 438 and 440, from which signals 442 and 444 are sent tocontroller 400. Line 446 provides yet another input to controller 400from left track motor 436. Right track pump 448 powers right track motor450 via lines 452 and 454, from which signals 456 and 458 are sent tocontroller 400. Line 460 provides yet another input to controller 400from right track motor 436. Finally, controller 400 communicates withleft track pump 434 via line 462 and with right track pump 448 via line464. All equipment is conventional in nature and design.

[0110] One condition that requires special attention for a trackedarticulated combine is when the operator desires to commence movement(forward or reverse) from a standing or stop position with the steeringwheel in a turning mode. Such initial turning movement requires tracks30/32 to slide from rest, which requires a great amount of force/torqueto overcome the consequent track friction with the ground. Theabove-described steering scheme can accommodate such conditions byinitiating the turn with the articulation cylinders augmented bypowering up only the outside track.

[0111] While combine 10 has been described as having non-steerablewheels, it should be appreciated that combine 10 can be designed to havesteerable front wheels. Thus, steering of combine 10 can result from oneor a combination of steerable forward unit wheels, articulationcylinders, and steerable (e.g., by speed differential or by wheelturning) rearward tracks (or tired wheels).

[0112] Finally, it should be appreciated also that some and/or all ofthe hydraulic motors, valves, pumps, and the like, can be replaced bypneumatic motors and associated equipment, electric motors andassociated equipment, or by any other power generating device or system,so long as the design and operation remains with the precepts of thepresent invention.

[0113] While the invention has been described with reference to apreferred embodiment, those skilled in the art will understand thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the appendedclaims. In this application all units are in the metric system and allamounts and percentages are by weight, unless otherwise expresslyindicated. Also, all citations referred herein are expresslyincorporated herein by reference.

We claim:
 1. A combine having increased on-board grain storage capacity,which comprises: (a) a forward unit having an operator's cab, an engine,a grain harvesting assembly, a grain transfer assembly, and being devoidof an on-board grain bin; and (b) a rearward unit attached by a joint tosaid forward unit and having, a powered wheel assembly, an on-boardgrain bin for receiving grain from said forward section grain transferassembly, and a grain offloading assembly.
 2. The combine of claim 1,wherein said rearward unit grain bin has a capacity of between about 500and 1,200 bushels.
 3. The combine of claim 1, wherein said forward unithas a wheel pair which is powered but not steerable.
 4. The combine ofclaim 1, wherein said rearward unit wheel assembly is selected from onewheel pair or multiple wheel pairs.
 5. The combine of claim 1, whereinsaid joint comprises: (a) an upper frame member carried by said forwardunit and having a recess on its lower side; (b) a lower frame membercarried by said forward unit, having a recess on its upper side, andbeing spaced-apart vertically below said upper frame member so that saidrecesses are in vertical registration; (c) a shaft carried by said rearunit; and (d) a bearing retainer assembly carried by the end of saidshaft and disposed between said recesses, and comprising: (i) an outerannulus surmounting an inner hub which hub is connected to said shaftwith thrust bearings inserted between said annulus and said hub, wherebythe inner hub co-rotates with shaft with respect to the outer annulus;(ii) a pair of nibs carried by said outer annulus which nibs reside insaid upper and lower recesses and which nibs are associated with taperedroller bearings so that said outer annulus co-twists with said shaftrespect to said forward unit; said joint being stiff in the longitudinalaxis formed along the forward unit frame members and rear unit shaft. 6.The combine of claim 5, wherein: (e) said upper frame (a) has a recesson its upper side and lower frame (b) has a recess on its lower side,all of said recesses being in vertical registration; (f) a first flangedplug is inserted into said upper frame upper recess, said flanged plughaving a flange that overlaps said frame member into which it isinserted, a thrust bearing being inserted in said recess adjacent saidflanged plug and said flange; and (g) a second flanged plug is insertedinto said lower frame lower recess, said flanged plug having a flangethat overlaps said frame member into which said flanged plug isinserted, a thrust bearing being inserted in said recess adjacent saidflanged plug and said flange.
 7. The combine of claim 1, wherein saidgrain transfer assembly for transferring grain from said forward unit tosaid rearward unit grain bin comprises: (a) said rearward unit carryingan onboard grain bin and having a front wall that has a horizontal slottherein, said front wall retaining a horizontally elongate graintransfer trough affixed thereto which trough is curved to match theradius of articulation of the combine and which trough is incommunication with said bin via said slot; and (b) said forward unitcarrying a grain transfer assembly comprising a fixed elongate dischargechute that empties into said rearward unit trough while said forward andrearward units are being turned about said joint.
 8. The combine ofclaim 7, wherein said trough is fitted with a floor that slopesdownwardly to said front wall slot.
 9. The combine of claim 1, whereinsaid grain off-loading assembly comprises: (a) a distal frame nestedwithin a proximal frame, the distal frame being extensible from andretractable into said proximal frame, said distal frame having adischarge end for discharging grain, said proximal frame having a feedend for receiving grain from said grain bin and a distal end from whichsaid nested distal fame extends and retracts; and (b) a conveyor systemcomprising a first fixed pulley located at the feed end of said proximalframe, a second fixed pulley located at the discharge end of the distalframe, a third fixed pulley located at the distal end of said proximalframe, and a fourth moveable pulley disposed within said proximal frameintermediate said first and third fixed pulleys, said conveyor extendingfrom said first pulley to said second pulley to said fourth pulley tosaid third pulley and back to said first pulley, whereby said conveyorextends as said distal conveyor extends and retracts as said distalconveyor retracts by movement of said fourth pulley.
 10. The combine ofclaim 1, wherein said grain off-loading assembly for unloading cleangrain from a combine grain bin, wherein a combine harvests grain anddeans it to provide said clean grain comprises: (a) a vertical flightedconveyor that operates in both directions; (b) a housing in which saidvertical flighted conveyor is disposed, said housing fitted at its topwith a bin spout, a discharge spout, a moveable door that permitscommunication of said flighted conveyor either with said bin spout orwith said discharge spout, a first opening at its bottom covered with amoveable door for permitting grain in said bin to be moved into saidhousing for conveying by said flighted conveyor, and a second opening atits bottom for permitting clean grain to be passed into said housingfrom said combine.
 11. The combine of claim 10, wherein a horizontalflighted conveyer is disposed along the bottom of said grain bin to feedgrain to said housing.
 12. The combine of claim 11, wherein saidhorizontal flighted conveyor is reversible.
 13. The combine of claim 11,wherein a floor is disposed above said horizontal flighted conveyor,said floor containing adjustable slots that regulate the rate of flow ofgrain fed to said horizontal flighted conveyor from said bin.
 14. Thecombine of claim 1, wherein said forward unit has a wheel pair which isone or more of powered or steerable.
 15. The combine of claim 1, whereinsaid forward unit has a powered front wheel pair and a rear caster wheelpair.
 16. The combine of claim 14, wherein said forward unit has apowered front wheel pair and a rear caster wheel pair
 17. A joint for apowered articulated vehicle for joining a forward unit to a rear unit,which comprises: (a) an upper frame member carried by said forward unitand having a recess on its lower side; (b) a lower frame member carriedby said forward unit, having a recess on its upper side, and beingspaced-apart vertically below said upper frame member so that saidrecesses are in vertical registration; (c) a shaft carried by saidrearward unit; and (d) a bearing retainer assembly carried by the end ofsaid shaft and disposed between said recesses, and comprising: (i) anouter annulus surmounting an inner hub which hub is connected to saidshaft with thrust bearings inserted between said annulus and said hub,whereby the inner hub co-rotates with shaft with respect to the outerannulus; (ii) a pair of nibs carried by said outer annulus which nibsreside in said upper and lower recesses and which nibs are associatedwith tapered roller bearings so that said outer annulus co-twists withsaid shaft respect to said forward unit; said joint being stiff in thelongitudinal axis formed along the forward unit frame members and rearunit shaft.
 18. The joint of claim 17, wherein (e) said upper frame (a)has a recess on its upper side and lower frame (b) has a recess on itslower frame, all of said recesses being in vertical registration; (f) afirst flanged plug assembly is inserted into said upper frame upperrecess, said flanged plug having a flange that overlaps said framemember into which R is inserted, a thrust bearing being inserted in saidrecess adjacent said flanged plug and said flange; and (g) a secondflanged plug assembly is inserted into said lower frame lower recess,said flanged plug having a flange that overlaps said frame member intowhich said flanged plug is inserted, a thrust bearing being inserted insaid recess adjacent said flanged plug and said flange.
 19. The joint ofclaim 18, wherein an articulated steering cylinder is disposed on eachside of said joint.
 20. The joint of claim 18, wherein said articulatedvehicle is a combine. &&. The joint of claim 17, wherein said upper andlower frame members are carried by said rearward unit, and said shaft iscarried by said forward unit. &&′. The joint of claim 18, wherein saidupper and lower frame members are carried by said rearward unit, andsaid shaft is carried by said forward unit.
 21. In improved combineincluding a forward unit connected by a joint to a rearward unit, theimprovement for transferring clean grain from said forward unit to saidrearward unit, which comprises: (a) said rearward unit carrying anonboard grain bin and having a front wall that has a horizontal slottherein, said front wall retaining a horizontally elongate graintransfer trough affixed thereto which trough is curved to match theradius of articulation of the combine and which trough is incommunication with said bin via said slot; and (b) said forward unitcarrying a grain transfer assembly comprising a fixed elongate dischargechute that empties into said rearward unit trough while said forward andrearward units are being turned about said joint.
 22. The combine ofclaim 21, wherein said trough is fitted with a floor that slopesdownwardly to said front wall slot.
 23. The combine of claim 22, whereinsaid grain bin is fitted with a vertical grain conveyor that is incommunication with said slot, wherein said vertical grain conveyordistributes grain from said trough to said bin.
 24. The combine of claim21 which is an articulated combine.
 25. The combine of claim 21, whereinsaid rearward unit is a grain cart being towed by said combine.
 26. Thecombine of claim 25, wherein said grain cart is powered and steerable.27. A grain unloading assembly for unloading clean grain from a combinegrain bin, wherein a combine harvests grain and cleans it to providesaid clean grain, which comprises: (a) a vertical flighted conveyor thatoperates in both directions; (b) a housing in which said verticalflighted conveyor is disposed, said housing fitted at its top with a binspout, a discharge spout, a moveable door that permits communication ofsaid flighted conveyor either with said bin spout or with said dischargespout, a first opening at its bottom covered with a moveable door forpermitting grain in said bin to be moved into said housing for conveyingby said flighted conveyor, and a second opening at its bottom forpermitting clean grain to be passed into said housing from said combine.28. The grain unloading assembly of claim 27, wherein a horizontalflighted conveyer is disposed along the bottom of said grain bin to feedgrain to said housing.
 29. The grain unloading assembly of claim 28,wherein two of side-by-side flighted conveyers are disposed along thebottom of said grain bin to feed grain to said housing.
 30. The grainunloading assembly of claim 28, wherein a floor is disposed above saidhorizontal flighted conveyor, said floor containing adjustable slotsthat regulate the rate of flow of grain fed to said horizontal flightedconveyor from said bin.
 31. The grain unloading assembly of claim 28,wherein said horizontal flighted conveyer runs reversibly in bothdirections.
 32. The grain unloading assembly of claim 27, wherein saidgrain bin is carried by a grain cart being towed by a combine.
 33. Thegrain unloading assembly of claim 32, wherein said grain cart is poweredand steerable.
 34. The grain unloading assembly of claim 27, whereinsaid grain bin is carried by a rear unit of an articulated combine. 35.An unload assembly for unloading dean grain from a combine grain bin,which comprises: (a) a distal frame nested within a proximal frame, thedistal frame being extensible from and retractable into said proximalframe, said distal frame having a discharge end for discharging grain,said proximal frame having a feed end for receiving grain from saidgrain bin and a distal end from which said nested distal fame extendsand retracts; and (b) a conveyor system comprising a first fixed pulleylocated at the feed end of said proximal frame, a second fixed pulleylocated at the discharge end of the distal frame, a third fixed pulleylocated at the distal end of said proximal frame, and a fourth moveablepulley disposed within said proximal frame intermediate said first andthird fixed pulleys, a conveyor belt extending from said first pulley tosaid second pulley to said fourth pulley to said third pulley and backto said first pulley, whereby said conveyor belt extends as said distalframe extends and retracts as said distal frame retracts by movement ofsaid fourth pulley.
 36. The unload assembly of claim 35, wherein a fifthpulley is located near said first fixed pulley to increase the wrapangle of said conveyor belt around said first fixed pulley.
 37. Theunload assembly of claim 35, wherein said proximal and distal frames areenclosed.
 38. The unload assembly of claim 35, which is moveable from arest position vertically to an unload position.
 39. The unload assemblyof claim 38, which is moveable laterally from side to side when it israised vertically to said unload position.
 40. The unload assembly ofclaim 35, which is controlled by an operator joystick which is fittedwith a first hand-activated switch which controls the vertical movementof said unload assembly, a second hand-activated switch which controlsinching of a combine associated with said unload assembly, a thirdhand-activated on-off switch for said unload assembly, a fourthhand-activated switch which returns the unload assembly to its homeposition; said joystick moving forward to extend said distal frame,backwards to retract said distal frame, left to rotate said unloadassembly to the left, right to rotate said unload assembly to the right,and rotatable to control the speed of said conveyor belt of said unloadassembly.
 41. The unload assembly of claim 40, wherein the controls forcontrolling said unload assembly also controls inching of said combineduring use of said unload assembly.
 42. The unload assembly of claim 38,which is carried by a rearward unit of an articulated combine comprisinga forward unit and said rearward unit, wherein said forward unit carriesa cradle that retains said unload assembly and accommodates relativemotion between said forward unit and said rearward unit when saidarticulated combine is turned.
 43. The unload assembly of claim 38 whichis carried by a grain cart that is towed by a combine, wherein saidcombine carries a cradle that retains and accommodates relative motionof said unload assembly relative to said combine when said combine isturned.
 44. The unload assembly of claim 42, wherein said cradlecomprises a series of adjacent rollers that are higher on each end ofsaid cradle.
 45. The unload assembly of claim 43, wherein said cradlecomprises a series of adjacent rollers that are higher on each end ofsaid cradle.
 46. The unload assembly of claim 35, wherein, said grainbin is carried by a grain cart being towed by a combine.
 47. The grainunloading assembly of claim 46, wherein said grain cart is powered andsteerable.
 48. The grain unloading assembly of claim 35, wherein saidgrain bin is carried by a rear unit of an articulated combine.
 49. Astraw and chaff spreader for mounting in association with a graincleaner of a combine, which comprises: a pair of generallyhorizontally-disposed, outwardly rotating, cleated conveyors disposed toreceive straw and chaff discharged from the grain separator and cleanerof said combine.
 50. The straw and chaff spreader of claim 49, whereinboth of said conveyors independently reversibly rotate.
 51. An airbagsuspension for a vehicle, which comprises: (a) a vehicle frame having anaxle extending therefrom; (b) a longitudinal beam affixed to said axlewhich carries at least one wheel; and (c) an airbag assembly comprising(i) an upper plate extending from said vehicle frame (ii) a lower plateaffixed to said longitudinal beam; (iii) an airbag disposed between saidupper and lower plates; (v) a pair of vertical blocks having verticalslots, said blocks being carried by said lower plate; (vi) a pair ofcams carried by said upper plate and riding in said vertical slots. 52.The airbag suspension of claim 51, wherein said vehicle rides on a pairof endless tracks.
 53. The airbag suspension of claim 51, wherein saidvehicle rides on a pair of tired wheels.
 54. The airbag suspension ofclaim 51, wherein each end of said longitudinal beam can move verticallyabout 24 inches.
 55. The airbag suspension of claim 51, wherein saidairbags are nominally rated at 10,000 pounds.
 56. The airbag suspensionof claim 51, wherein said vehicle is an articulated combine.
 57. Theairbag suspension of claim 51, wherein said axle is a stub axle.
 58. Asteering system for an articulated vehicle having a joint that connectsa forward unit and a rearward unit and at least one articulationcylinder to provide a turning force at said joint, which comprises: (a)an operator steering mechanism whereby an operator can direct thedesired direction of said vehicle; (b) a power source for driving pumpsadapted to drive motors and cylinders; (c) said forward unit havingtractive wheels/tracks powered by one or more motors, each motor havinga transducer for measuring its rotational speed; (d) said rearward unithaving a pair of tractive endless tracks/wheels each powered by aseparate motor, each motor having a transducer for measuring itsrotational speed; (e) a programmable controller that receives therotational speed measurements from all of said transducers and operatorsteering commands from said steering mechanism, and which responds withsuitable outputs; and (f) actuators that receive said controller outputsand adjusts the output of each of said motors powering said rearwardunit tracks/wheels.
 59. The steering system of claim 58, which is one ormore of hydraulic, pneumatic, or electric.
 60. The steering system ofclaim 59, which is hydraulic and wherein said actuators are steppermotors that adjust the swash plate of said hydraulic pumps.
 61. Thesteering system of claim 57, which is hydraulic and wherein thehydraulic pressure at each motor has an associated transducer whichgenerates a signal that is fed to said programmable controller.
 62. Thesteering system of claim 60, wherein a relief valve is associated witheach hydraulic motor whereby the maximum torque of each hydraulic motoris determined by the setting on each relief valve.
 63. The steeringsystem of claim 58, wherein said rearward unit is fitted with a pair ofendless tracks.
 64. The steering system of claim 61, wherein saidrearward unit is fitted with a pair of endless tracks.
 65. The steeringsystem of claim 64, wherein the rearward unit track hydraulic motorsshare the forward and rearward propulsion of said articulated vehiclewhen the steering load on said articulation cylinder is less than apreset value, and assists the articulation cylinder when the steeringload is greater than said preset value.
 66. The steering system of claim65, wherein the rearward unit track hydraulic motors share the forwardand rearward propulsion of said articulated vehicle when the steeringload on said articulation cylinder is less than a preset value, andassists the articulation cylinder when the steering load is greater thansaid preset value.
 67. The steering system of claim 58, wherein theforward unit is wheeled.
 68. The steering system of claim 58, wherein apotentiometer is associated with said operator speed and directionmechanism as a speed reference and whose output is connected with saidprogrammable controller.
 69. The steering system of claim 58, whereinarticulated vehicle is an articulated combine.
 70. An improved combine,the improvement which comprises: (a) an overhead rail; and (b) a fueltank suspended from said overhead rail, said fuel tank being movableforwardly and rearwardly.
 71. The improved combine of claim 70, whichadditionally comprises an actuator connected to said fuel tank formoving said fuel tank forwardly and rearwardly.
 72. The improved combineof claim 72, wherein said combine is an articulated combine having aforward unit that carries said rail and fuel tank and a rearward unit.73. A method for articulating an articulated vehicle at a rest positionwherein said vehicle is composed of a forward unit and a trackedrearward unit having a pair of powered tracks, said forward and rearwardunits connected by a joint and an articulation cylinder, whichcomprises: powering up only one track while simultaneously actuatingsaid articulation cylinder.
 74. The method of claim 73, wherein saidrear unit tracks are powered by one or more of a hydraulic motor, apneumatic motor, or an electric motor.
 75. The method of claim 73,wherein one of said tracks is powered in the forward direction while theother of said tracks is powered in the rearward direction.
 76. Themethod of claim 73 wherein said articulated vehicle is an articulatedcombine.